Just looked up the official legislation Eddie. Parking on a private road is the same as parking on private land and can be considered as trespass.
I ploughed through a document which if you Google PDF roads - unadopted: parliament gives loads of information.
6 Parking
Further information on parking more generally can be found in HC Library standard note
SN/BT/2235.
In terms of parking, there is no general right to park in a private road except for the owner of
the road. In practice parking may be permitted or tolerated by the owner (in which case there
is a licence to park) and in some cases a legal right may have been granted by the owner.
Parking in a private road without permission or a legal right to do so is trespassing, and is a
civil wrong for which redress can be obtained. The wrong is done to the owner of the road.
He can bring legal proceedings to obtain compensation, though the amount of harm done
would typically be small and the compensation therefore very modest. The owner is also
entitled to insist that trespassing ceases, and could if need be obtain an injunction against
the person concerned.
Whether or not someone is trespassing by parking in a private road, if they obstruct the road
and so interfere with its use by those with private rights of way, a different civil wrong
(nuisance) is committed. In this case, the civil wrong would be against the person whose land
has the benefit of the right of way, probably the owners of the properties. The same would
also be true if a parked car obstructed access to a private road. In a case of nuisance the